The data type GM_Position is a union type consisting of either a DirectPosition or of a reference to a GM_Point from which a DirectPosition shall be obtained. The use of this data type allows the identification of a position either directly as a coordinate (variant direct) or indirectly as a reference to a GM_Point (variant indirect).<br/>GM_Position::direct [0,1] : DirectPosition; <br/>GM_Position::indirect [0,1] : GM_PointRef;<br/><br/>GM_Position:<br/> {direct.isNull = indirect.isNotNull}<br/>